On Tue, Nov 10, 2020 at 07:05:18PM +0100, Sebastian Andrzej Siewior wrote: > On 2020-11-09 15:37:03 [+0100], Daniel Wagner wrote: > > > I've been staring at the code of signaltest on Friday and I might need > > > to stare longer to figure out what it does. > > > > I hear you. Anyway, I gave the current head a run with lazy preemption > > disabled as you asked for. > > I just sent a few patches your way regarding signaltest. It should help > you with tracing. I've been playing with it on a juno box and I didn't > see anything odd. My max value was below 200us. I added a few tracing > bits. With sched, signal and hrtimer events you should be able to see > what delays the RT thread. I didn't see anything odd. With the current version signaltest + your test patch and 'taskset -c1' the results looks good again, around 230us (running since 2 hours). I've tested first without taskset and it took about an half hour to hit 350us. So pinning the threads on one CPU fixes it. I think we change signaltest to use the correct affinity on default. Also, I see that sigwaittest has some code for it, but it, but it would be a good idea to set the defaults so that out of the box the test does the right thing. I'm sorry about dragging you into this problem.
